The USB 3.0/eSATA 4-Bay 3.5" SATA 6Gb/s Hard Drive Enclosure with built-in Hard Drive Fan and UASP lets you install four 3.5” SATA hard drives into an external enclosure, and connect to your computer through USB 3.0 or eSATA. For fast performance and efficient data transfers, the enclosure supports SATA 6Gb/s transfer speeds when connected through eSATA. The versatile enclosure can also be connected through USB 3.0, with support for UASP, performing up to 70 percent faster than conventional USB 3.0 when paired with a UASP-enabled host controller.